My first tip for reducing food waste is to use a meal planner. I usually fill this out at the weekend for the following week; I have a rummage through my fridge and freezer to see what needs using and I make a shopping list for anything else that's needed at the same time. I also cross reference it with my son's school dinner menu which is posted online.
It really takes the stress out of meal planning in the week as I don't have to think about what I'm cooking (or reheating!) that evening. I check it in the morning and get anything that needs defrosting out of the freezer. We only plan our main meal (dinner) as we are mostly at work/school during the day, and I prefer to freewheel a bit at the weekend but you can plan all your meals this way (great if you're on a healthy eating programme). I sometimes swap meals around once the week starts as some days you just don't fancy what's planned! I printed this planner from here https://www.theorganisedmum.blog/ and I laminated it so I can reuse it week after week, but there are also some great apps if you prefer to organise yourself digitally